Island Park

Snowpit at the Head of Hellroaring Creek on 1/7/24. Note the two stripes of surface hoar in the pit wall.

We measured 16" of low-density snow equaling 0.7" of snow water equivalent at higher elevations in the Centennial Mountains of Island Park, ID. The new snow is sitting on a couple of layers of feathery surface hoar and a weak snowpack. It will not take much wind, settlement, or new snow to push the snowpack to the breaking point. Photo: GNFAC

We rode up to the head of Yale Creek, down a bit into the head of Hellroaring Creek and then returned via the East Fork of Hotel Creek. The depth of new snow increased dramatically with elevation from approximately 8" (0.5" SWE) at 8000 ft to 18" (0.7" SWE) at 9000 ft. The new snow had little cohesion. 

We found buried surface hoar on both shady and sunny slopes. Sunny slopes had multiple melt-freeze crusts interspersed with weak facets throughout the pack. On shady slopes the lower snowpack was entirely faceted. We had an ECTP11 on facets just below the old snow surface on a S facing slope. Otherwise our results were ECTX and ECTN with slab fracture in Propagation Saw Tests (likely because neither the facets or new snow were cohesive enough to act as a slab in our tests).

Wind, settlement or more snow could quickly make for a cohesive slab. When that happens, with so much new snow and such weak snow beneath it conditions will rapidly become unstable. 

We saw no avalanche activity and had no cracking or collapsing. 

New snow in Island Park made for beautiful views and heightened avalanche danger as the new snow fell on a snowpack riddled with weak layers. Photo: GNFAC